Preparation of synthetic film materials

ABSTRACT

A PROCESS FOR PRODUCING FILM BASE MATERIAL CONSISTING OF BIAXIALLY ORIENTATED AND HEATSET POLYETHYLENE TEREPHTHALATE HAVING A SUPERIMPOSES LAYER CONSISTING OF HOMOPOLYMERS OF VINYL HALOGENOACETATE AND VINYL CYANOCAETATE OR COPOLYMERS THEREOF WITH UNSATURATED CARBOXYLIC ACIDS, VINYL ACETATE OR VINYL ALCOHOL WHEREIN THE SUPERIMPOSED LAYER MAY BE APPLIED BEFORE OR AFTER ORIENTATION.

United States Patent 3,573,951 PREPARATION OF SYNTHETIC FILM MATERIALSTerence Arnold Abbott, Basil R. Shephard, David Rankine Kennedy, andMargaret London Clachan, Brantham, Manningtree, Essex, England,assignors to Bexford Limited, Brantham, Manningtree, Essex, England NoDrawing. Continuation-impart of application Ser. No. 511,980, Dec. 6,1965, now Patent No. 3,506,445. This application Sept. 22, 1966, Ser.No. 581,182 Claims priority, application Great Britain, Dec. 9, 1964,50,118/64 The portion of the term of the patent subsequent to Apr. 14,1987, has been disclaimed Int. Cl. G03c 1 80; 132% 7/24 US. Cl. 117-7 2Claims ABSTRACT OF THE DISCLOSURE A process for producing film basematerial consisting of biaxially orientated and heatset polyethyleneterephthalate having a superimposed layer consisting of homopolymers ofvinyl halogenoacetate and vinyl cyanocaetate or copolymers thereof withunsaturated carboxylic acids, vinyl acetate or vinyl alcohol wherein thesuperimposed layer may be applied before or after orientation.

This application is a continuation-in-part of our US. application Ser.No. 511,980 filed on Dec. 6, 1965, entitled Synthetic Film Materials,now Pat. No. 3,506,445.

This invention relates to synthetic film materials, and moreparticularly to film base materials of use in the production ofphotographic materials.

It is known that self-supporting films formed of synthetic linearhydrophobic materials, particularly of the polyesters formed by reactionof ethylene glycol and terephthalic acid, and synthetic polycarbonates,may be prepared with mechanical and physical and chemical propertieswhich, for example, render them very suitable indeed as base materialson which may be coated silver halide photographic emulsion layers forthe production of photographic film materials.

However, since such base materials are inherently highly hydrophobic andthe usual gelatino silver halide emulsions are highly hydrophilic, thereis great difiiculty in securing adequate anchorage between the base filmand the emulsion layer, especially bearing in mind that the anchoragemust remain firm throughout the processing sequence of the finalphotographic film.

It is known to deal with such a difficulty by the provision of ananchoring layer or layers (so-called subbing layers) between the filmbase and the emulsion layer, and it is an object of the presentinvention to provide a new method of subbing synthetic linear polyesterand polycarbonate film base to render it adapted to accept, and holdstrongly adherent to it, a layer of a more hydrophilic nature, e.g. onehaving a basis of gelatin, such as a gelatino silver halide emulsionlayer.

According to a first feature of the present invention there is provideda film base material consisting of a film of synthetic linear polyesteror polycarbonate of highly hydrophobic character having superimposedthereon a layer adherent to said film, hereinafter referred to as layerA, which consists predominantly of a polyvinyl halogenoester, or apolyvinyl-cyanoester, or a copolymer of a vinylhalogenoester or avinyl-cyanoester with an alpha-beta unsaturated carboxylic acid or withvinyl acetate and/or vinyl alcohol.

The preferred polyvinyl-halogeno-esters for use in layer A arehomopolymers of vinyl mono-, dior tri-halogeno Patented Apr. 6, 1971acetate, especially vinyl mono-, dior tri-chloroacetate, and polyvinylmonocyanoacetate.

The preferred copolymers for use in layer A are copolymers of vinylmono-, dior tri-halogeno-acetate, especially vinyl mono-, diortri-chloroacetate or vinylmonocyano-acetate with 1 to mole percent of analpha-beta unsaturated carboxylic acid such as crotonic acid, or with 1to 60 mole percent of vinylacetate and/ or vinyl alcohol.

The homo-polymers of the class defined above may be readily prepared bypolymerisation of vinyl mono-, dior tri-halogeno-acetate orvinylmono-cyano-acetate monomer, or alternatively by the completehalogeno-acetylation or cyano-acetylation of polyvinyl alcohol. Thecopolymers with alpha-beta unsaturated carboxylic acids may be preparedby copolymerisation of vinyl mono-, dior tri-halogeno acetate or vinylmono-cyano-acetate monomer with an alpha-beta unsaturated carboxylicacid. The copolymers with vinyl acetate and/ or vinyl alcohol may beprepared by copolymerisation of vinyl mono-, dior tri-halogeno acetateor vinyl mono-cyano-acetate with vinyl acetate op tionally withsubsequent partial hydrolysis to introduce free hydroxyl groups;alternatively these copolymers may be prepared by directhalogeno-acetylation or cyanoacetylation of suitable starting materialssuch as commercial polyvinyl acetates or polyvinyl alcohols.

A valuable property of the copolymers as defined for layer A is theirability to be readily cross-linked so that the efiect of solvents andtemperature on the final products is minimal. Suitable cross-linkingagents include tetraalkoxy titanium compounds, tetra-alkoxy zirconiumcompounds, formaldehyde liberators such as paraformaldehyde, dimethylolurea and heXa-methoxymethyl melamine, and di-isocyanates anddi-anhydrides. These cross-linking agents may be added in amounts up to20% by the weight of the copolymer.

The preferred cross-linking agents for use in the invention aretetra-isopropyl-titanate and hexa-methoxy methyl melamine.

A film base material as defined above will accept with good anchorage amore hydrophilic layer such as a layer of gelatin applied from organicsolvent dispersion, hereinafter referred to as layer B or alternativelygelatin together with one of the copolymers of the type defined above asbeing used in layer A, applied from organic solvent dispersion,hereinafter referred to as layer B or alternatively gelatin togetherwith a polyvinyl acetate applied from organic solvent dispersion,hereinafter referred to as layer B Copolymers Within the class definedwhich are particularly suitable for inclusion together with gelatin toform layer B are those which have 30-60 mole percent of structural unitsderived from an alpha-beta unsaturated carboxylic acid, or 30 to 60 molepercent of structural units derived from vinyl acetate and/ or vinylalcohol.

The copolymers of the defined class when used in layer B can becross-linked in the same way as when they are used in layer A.

Suitable polyvinyl acetates for use in layer B are readily availablecommercially under the Trademark Mowolith.

A film base material as defined above in which layer A is supercoatedwith a layer B B or B is particularly adapted to accept and holdadherent to its aqueous based gelatin compositions such as agelatino-silver-halide emulsion layer. This resultant product is of useas photographic material.

In a further embodiment of the invention in order to obtain the greatestadhesion of an aqueous based gelatine composition to a hydrophic basematerial which is coated with a layer A and with a layer B B or B it ispreferred that layer A consists predominately of a copolymer, within theclass defined which has from 10 to 30 mole percent of structural unitsderived from an alphabeta unsaturated carboxylic acid or from to 30 molepercent of structural units derived from vinyl acetate and/ or vinylalcohol.

In another embodiment of the invention a film base material as definedabove will accept with good anchorage on to the surface of layer A acellulose acetate layer. This cellulose acetate layer may afterwards behydrolysed on its outer surface and impregnated with a light sensitivediazonium salt or may be directly impregnated with a light sensitivediazonium salt contained in an attacking solvent medium, to produce adiazotype film material.

In a further embodiment of the invention a film base material as definedabove will accept with good anchorage onto the surface of layer A alayer of polyvinyl acetal which may be directly impregnated by a lightsensitive diazonium salt, contained in an attacking solvent medium, toproduce a diazotype film material.

In a still further embodiment of the invention a film base material asdefined above will accept with good anchorage on to the surface of layerA a layer of partially hydrolysed polyvinyl acetate which includes alight sensitive diazonium salt or which is subsequently impregnated withsuch a salt.

In another preferred embodiment of the invention where the film base isa film of a synthetic linear poly ester, in order to assist in keyinglayer A to the hydrophobic film material the said base material istreated with a substance or mixture of substances having a. swelling orsolvent action on the base. Any of the known swelling agents or solventsfor synthetic linear polyester may be used including chloro-substitutedaliphatic acids such as trichloroacetic acid, phenols,chloro-substituted phenols such as mono-, di-, and tri-chlorphenol, andaromatic alcohols. These swelling agents or solvents may be convenientlyapplied to the base in the form of solutions and the base then heatedfor a short time at an elevated temperature to remove the solvent mediaand accelerate the action of the swelling agent on the base.

Alternatively to assist in keying layer A, to synthetic linear polyesterbase, substances or mixtures of substances having a swelling or solventaction on the base may be included as minor proportions of the solventmedia for layer A.

Where it is desired that the final film base products are to be colouredor tinted, dyes or pigments may be included, dissolved or dispered inany of the layers described above, as appropriate to give the requiredcolour and density. Where the base used is one of a synthetic linearpolyester the dyes or pigment may alternatively be included togetherwith the swelling agent in the pre liminary treatment of the base.

The film products of this invention may be prepared by successivelycoating synthetic linear polyester or synthetic linear polycarbonatebase with the layers as described above, each layer being dissolved ordispersed in a volatile organic solvent medium and being dried beforeanother is applied.

Layer A may conveniently be applied from solvent media containing lowerketones such as acetone or methyl ethyle ketone, alcohols such as methylor ethyl alcohol or chlorinated hydrocarbons such as methylene chlorideand carbon tetrachloride.

In the case of the synthetic linear polycarbonate base, solvent mediawhich have excessive swelling action on the base such as thosecontaining high proportions of methylene chloride are to be avoidedsince they may cause distortion of the base. Solvent media which containhigh proportions of lower ketones should similarly be avoided since theymay cause crazing of the polycarbonate base.

The hydrophilic gelatin layers B B and B may be applied from solventmixtures containing lower alcohols or ketones, the ketones constitutingless than 50% of the mixture to avoid excessive swelling action on thepreceding layer.

In another embodiment of the invention where the film base is a film ofpolyethylene terephthalate polyester it is possible to coat the layer Athereon before the film of polyethylene terephthalate has been fullyorientated. By fully orientated is meant the process wherebypolyethylene terephthalate film is made dimensionally stable andstronger. One method of fully orinetating polyethylene terephthalatefilm comprises stretching the film at C. in a longitudinal directionwith a draw ratio of 2.5-4.0 while the film is restrained from shrinkagein the other linear dimension, followed by stretching the film at 80120C. in the transverse direction with a similar draw ratio whilemaintaining suflicient tension in the already drawn longitudinaldirection to again avoid shrinkage. The film is finally heated at -250for some 0.55 minutes While being restrained from shrinkage in bothdimensions; the object of such heat-setting and similar annealingprocesses results in a film showing little or no shrinkage or re-heatingto moderate temperatures on a later occasion. As alternative processesfilm may also be drawn transversely prior to longitudinally, or may bebiaxially drawn in both dimensions simultaneously. The term orientatedas used in the specification refers only to film which has been bothbiaxially stretched and heat set.

Layer A may be applied to extruded amorphous polyethylene terephthalatefilm, to uniaxially stretched film, or to biaxially stretched film butbefore the heat setting step. It has been found that when layer A is soapplied there is often a greater adherence of the said layer A to thepolyethylene terephthalate film than when layer A is applied after thepolyethylene terephthalate has been fully orientated. It has also beenfound that the compounds which comprise layer A may be applied to theunorientated polyethylene terephthalate film as aqueous solutions orlattices and this method of coating avoids the use of costly organicsolvents which have to be recovered.

Halogen-containing phenolic substances as hereinbefore described whichhave slight swelling action on the surfaces of polyethyleneterephthalate can be applied to the polyethylene terephthalate filmbefore it has been fully orientated and before the layer A has beencoated thereon. This results in some cases in an improved adhesion oflayer A to the polyethylene terephthalate film. Application of the saidhalogen-containing phenolic substances can be made to the polyethyleneterephthalate by adding them to the coating solution of layer A.Alternatively pretreatment of polyethylene terephthalate film was bemade with the said phenolic halogen-containing substances dissolved orsuspended in water or dissolved in organic solvents.

In the treatment of amorphous polyethylene terephthalate with resinsand/or with phenolic halogen-containing substances it is necessary toavoid crystallization of polyethylene terephthalate, which occursreadily with solvent media which have swelling or dissolving action onthe amorphous film but which do not dissolve the material when it is inthe crystalline state. Therefore, it is preferred that the resins oflayer A and/ or a phenolic substance are applied with water as the mainsuspending or dissolving medium, or that a solvent having lower swellingpower for polyethylene terephthalate such as methanol, is used.

The following examples will serve to illustrate the invention:

In the following Examples 1-6, biaxially oriented polyester film Wasused.

EXAMPLE 1 Coat 1 A copolymer containing 55 mole percent vinylmonoacetate, 11 mole percent vinyl alcohol and 1 mole percent vinylacetate2.0 g.

Tetra isopropyl titanate0.1 ml.

Methylene chloride100 ml.

Dried for approximately 5 mins. at 60 C.

Coat 2 Gelatin-1.2 g.

Water- .0 ml.

Acetic acid-1.0 ml. Methanol95 ml.

Seasoned for mins. at 105 C.

EXAMPLE 2 Coat 1 A copolymer containing 90 mole percent vinylmonochloracetate and 10 mole percent crotonic acid2.0 g.

Tetra isopropyl titanate0.l ml.

Methylene chloride-100 ml.

Dried for approximately 5 minutes at C.

Coat 2 As for coat 2 in Example 1.

EXAMPLE 3 Coat 1 Polyvinyl monochloracetate2.0 g. Methylene ch1oride-l00ml. Coating dried for 5 mins. at 30 C.

EXAMPLE 4 Coat 1 Polyvinyl monochloracetate2.0 g. Methylene chloride-l00ml. Coating dried for 2 mins. at 30 C.

Coat 2 A copolymer containing 55 mole percent vinyl monochloracetate andmole percent vinyl alcohol2.0 g.

Acetone5'0 ml.

Methanol ml.

Ethyl lactate-3.0 ml.

Dries for approximately 5 mins. at 30 C.

Coat 3 As for coat 2 in Example 1. Seasoned for 15 mins. at 105 C.

EXAMPLE 5 Coat 1 A copolymer containing 70 mole percent vinylmonochloracetate, 29 mole percent vinyl alcohol and 1 mole percent vinylacetate-2.0 g.

Methylene chloride-100 ml.

Trichloracetic acid2.0 g.

Tetra isopropyl titanate-0.1 ml.

Dried for 5 mins. at C.

Coat 2 As for coat 2 in Example 1. Seasoned for 15 mins. at 105 C.

EXAMPLE 6 Coat 1 A copolymer containing mole percent vinyldichloracetate and 35 mole percent vinyl alcohol2.0 g.

Methylene chloride-100 ml.

Dried for 2 mins. at 60 C.

6 Coat 2 As for coat 2 in Example 1. Seasoned for 15 mins. at 105 C.

In the following Examples 7 to 10 the biaxially oriented polyester filmwas first treated with a solution containing: Trichloracetic acid5.0 g.

Sodium lauryl sulphate0.25 g.

Water100' ml.

and dried for 5 minutes at 60 C. Coatings were then applied as set outin the examples.

EXAMPLE 7 Coat 1 A copolymer containing 50 mole percent vinylmonocyanoacetate, 49 mole percent vinyl alcohol and 1 mole percent vinylacetate2.0 g.

Tetra isopropyl titanate0.1 ml.

Acetone99 ml.

Methanol1.0 ml.

Dried for 5 minutes at 60 C.

Coat 2 As for coat 2 in Example 1. Seasoned for 15 minutes at 105 C.

EXAMPLE 8 Coat 1 A copolymer containing 74 mole percent vinylmonobromacetate, 25 mole percent vinyl alcohol and 1 mole percent vinylacetate2.0 g.

Methylene chloride-100 ml.

Dried for 5 minutes at 60 C.

Coat 2 As for coat 2 in Example 1. Seasoned for 15 minutes at 105 C.

EXAMPLE 9 Coat 1 A copolymer containing mole percent vinylmonochloracetate and 15 mole percent crotonic acid1.0 g.

Tetra-isopropyl-titanate-0.1 ml.

Methyl ethyl ketonel00 ml.

Isopropyl alcohol-1.0 ml.

Coat 2 As for coat 2 in Example 1. Seasoned for 15 minutes at 105 C.

EXAMPLE 10 Coat l A copolymer containing 65 mole percent vinylmonochloracetate, 13 mole percent vinyl alcohol and 22 mole percentvinyl acetate-2.0 g.

Hexa-methoxymethyl melan1ine0.1 g.

Acetone99 ml.

Methanol1.0 ml.

Ethyl lactatae3.0 ml.

Dried for 2 minutes at 30 C.

Coat 2 As for coat 2 in Example 1. Seasoned for 15 minutes at 105 C.

EXAMPLE 11 Biaxially orientated polyester film Was treated with thefollowing solution:

2,4,6-trichlorphenol-3.0 g. 2,4-dichlorphenol2.0 g. Methanol100 ml.

After drying for 5 minutes at 60 C. the following coats were applied:

Coat 1 A copolymer containing 70- mole percent vinyl monochloracetate,29 mole percent vinyl alcohol and 1 mole 5 percent vinyl acetatel.0 g.

Acetone-97 ml.

Ethyl lactate3.0 ml.

Dried for 5 minutes at 60 C.

Coat 2 As for coat 2 in Example 1. Seasoned for 15 minutes at 10 5' C.

EXAMPLE 12 Biaxially oriented polyester film was treated with thefollowing solution:

2,4,6-trichlorophenol2.5 g. 2,4-dichlorphenol-8.5 g. Methanol-l00 ml.

After drying for mins. at 60 C. the following coats were applied:

Coat 1 Coat 2 Gelatin-1.4 g. Polyvinyl acetate (Mowolith)0.1 g. Water5.0rml.

Acetic acidl.0 ml.

Methanol94 ml.

Formaldehyde solution)0.1 ml.

EXAMPLE 13 To biaxially oriented polyester film were applied thefollowing coats:

Coat 1 A copolymer containing 55 mole percent vinyl monochloracetate, 44mole percent vinyl alcohol and 1 mole percent vinyl acetate0.5 g.

2,4,6-trichlorphenol3.5 g.

2,4-dichlorophenol3.5 g.

Acetone100 ml.

Dried for 2 minutes at 90 C.

Coat 2 As in Example 12 above.

EXAMPLE 14 Biaxially oriented polyester film was treated with thefollowing solution, which included a blue dye to give a finally preparedfilm base of uniform blue tint.

2,4,'6-trichlorphenol1.0 g. 2,4-dichlorophenol-1.0 g.

Alizarin pure Blue Base B-0.15 g. Methyl ethyl ketone100 ml.

After drying for 2 minutes at 80 C., the following coats were applied:

Coat 1 8 Acetone-$6.0 ml. Ethyl lactate3.0 ml. Dried for 5 minutes at 60C.

Coat 2 As for coat 2 in Example 1. Seasoned for 10 minutes at C.

EXAMPLE 15 In the following example polycarbonate film was coated with:

Coat 1 A copolymer containing 70 mole percent vinyl monochloracetate, 29mole percent vinyl alcohol and 1 mole percent vinyl acetate-1.0 g.Tetra-isopropyl titanate0.l ml. Acetone-40 ml. Methanol60 m1. Ethyllactate3.0 ml. Dried for 2 minutes at 30 C.

Coat 2 As for coat 2 in Example 1. Seasoned for 15 minutes at C.

A photographic gelatino silver halide emulsion coating was applieddirectly on to the top coating of the filim products of Examples l-lland 14 and 15. The layers were strongly adherent to one another and tothe film support, so that the final photographic film could be processedwithout danger of separation of the layers or frilling.

Biaxially oriented polyester film was pretreated and a first coatapplied as in Example 11.

A subsequent coating of secondary cellulose acetate was applied directlyto this first coat, adhered strongly to it and was subjected to alkalinehydrolysis in a manner known per se to provide hydrolysed surface, andthis was impregnated with a solution of a light sensitive diazoniumcompound to yield as end product a light sensitive film for diazo typeprinting.

EXAMPLE 17 Biaxially orientated polyester film was pretreated and afirst coat applied as in Example 11.

A second coat of hydrolysed polyvinylacetate was applied directly tothis first coat adhered to it. This second coat could contain a lightsensitive diazonium compound or could be impregnated with a lightsensitive diazonium compound to produce a diazo-type material.

EXAMPLE 18 Biaxially oriented polyester film was pretreated and a firstcoat applied as in Example 11.

A second coat of a polyvinyl acetal resin was applied directly to thisfirst coat and adhered strongly to it. This second coat could beimpregnated directly with a light sensitive diazonium compound containedin a solvent medium having a swelling or solvent action on the polyvinylacetal, without loss of adhesion of the polyvinyl acetal coat to thepolyester film, to produce a diazo-type material.

In the following Examples v19-30 layer A was applied to polyesterterephthalate film base before the film base had been fully biaxiallyorientated and heat set.

EXAMPLE 19 Polyvinyl chloracetate-alcohol prepared by heating polyvinylalcohol with chloracetic acid until 50% of the hydroxyl groups werechloracetylated was prepared as an aqueous dispersion containing 1%resin solids. Amorphous polyethylene terephthalate was coated with thedispersion and stretched three times in both linear dimensions whilebeing heated at 100 C. After heating at C.

with prevention of retraction and cooling, the film was re-coated with adispersion of gelatine in 6% aqueous methanol containing 1% solids anddried.

The gelatine-coated film was tested for adhesion by scoring lightly witha razor blade, attaching adhesive tape and rapidly ripping off the tape.No removal of the coated layer could be obtained. The gelatine-coatedfilm was further tested by applying a layer of gelatino-silver halideemulsion to give a completed photographic film. Excellent adhesion ofthe emulsion was obtained initially, during wet processing in developer,stop-baths, fixers and washers and after drying.

EXAMPLE 20 The aqueous dispersion of resin used in Example 19 wasapplied to polyethylene terephthalate film after uniaxial stretching bya 1:3 ratio. After drying, the film was stretched similarily in theother linear dimension and the processes completed to a gelatine-coatedfilm as described in Example 1.

EXAMPLE 21 A resin dispersion was prepared as in Example I having 3%solids content of 50 mole percent polyvinylchloracetate-alcohol. Thedispersion was applied to biaxially oriented polyethylene terephthalateprior to heat-setting the film at 180 C. The coated and stabilised filmwas recoated with gelatine as described in Example 1.

EXAMPLE 22 A latex was prepared by emulsion polymerisation usinghydrogen peroxide as a catalyst of vinyl chloracetate containing solids.

The latex was applied to amorphous polyethylene terephthalate film whenthe film was biaxially oriented, heatset and coated with gelatine asdescribed in Example .1.

EXAMPLE 23 Amorphous polyethylene terephthalate was pre-treated with a1% methanol solution of parachlorophenol followed by coating with a 3%latex of polyvinyl chloracetate. Processes to a gelatin-coated productwere completed as described in Example 1.

EXAMPLE 24 A latex was prepared containing solids of vinylchloroacetatecrotonic acid copolymer having 5 mole percent of the latter units. Thelatex was coated on amorphous polyethylene terephthalate which wasbiaxially orientated and heat-set as described.

The coated film was re-coated with a gelatine dispension containinggelatine (1%) and vinyl chloracetatecrotonic acid copolymer (0.5%) in a1:1 methanol: acetone mixture containing 2% water.

EXAMPLE 25 Polyvinyl chloracetate-alcohol was prepared by heatingpolyvinyl alcohol with chloracetic acid until 35 mole percent of thehydroxyl groups were esterified.

The resin prepared as a 1% solution in methanol was applied to amorphouspolyethylene terephthalate followed by processes of biaxial stretching,heat-setting and gelatine coating as in Example 1.

EXAMPLE 26 A latex was prepared containing 5% solids of a vinylchloracetate-2-hydroxyethylmethacrylate copolymer having 10 mole percentof the latter units. This latex was used to coat amorphous polyester asdescribed in Example 1.

EXAMPLE 27 A latex of 6% solid content was prepared of polyvinylchloracetate-acrylamide containing 6 mole percent acrylamide and use tocoat uniaxially stretched polyethylene terephthalate as described inExample 2.

10 EXAMPLE 2:;

A latex was prepared of vinyl chloracetate-N-methylolacrylamide of 10%solids content and to ml. of this latex 2 g. of a 1:1 mixture of 2:4dichlorophenol and 224:6 trichlorophenol was added. The latex was usedto coat biaxially stretched polyethylene terephthalate prior toheat-setting, when processes of heat-setting and gelatine coating werecompleted as in Example 3.

EXAMPLE 29 Polyvinyl cyanacetate-alcohol prepared by heating polyvinylalcohol with cyanacetic acid until 45 mole percent of the hydroxylgroups were esterified was prepared as a 3% solution in methanolcontaining 10% acetone. To 100 ml. of this solution 2 g. ofparachloro-meta-cresol was added followed by application to amorphouspolyethylene terephthalate. The amorphous film was further treated asdescribed in Example 1.

EXAMPLE 30 Polyvinyl trichloracetate-alcohol was prepared by heatingpolyvinyl alcohol with trichloracetic acid until 60% of the hydroxylgroups were esterified.

A 2% dispersion of this polymer in water also containing 1%parachlorophenol was applied to amorphous polyethylene terephthalatefollowed by processes of hiaxial orientation, heat-setting and gelatinecoating as described in Example 1.

We claim as our invention:

1. In a process for the production of film base material consisting of afilm of biaxially oriented and heat-set polyethylene terephthalatehaving superimposed thereon a layer adherent to said film which consistspredominantly of a polymeric substance selected from the classconsisting of the homopolymers of vinyl mono-, diand tri-halogenoacetateand vinyl cyanoacetate and the copolymers thereof with at least onecopolymerizing substance selected from the class consisting ofalpha-beta unsaturated carboxylic acids, vinyl acetate and vinylalcohol, the said copolymerizing substance constituting 1 to 60 molepercent of the copolymer, the step of applying the said layer to thepolyethylene terephthalate film at any state before the polyethyleneterephthalate film has been fully biaxially orientated and heat-set.

2. In a process for the production of film base material consisting of afilm of biaxially orientated and heatset polyethylene terephthalatehaving superimposed thereon a layer adherent to said film which consistspredominantly of a polymeric substance selected from the classconsisting of the homopolymers of vinyl mono-, diand trihalogenoacetateand vinyl cyanoacetate, and the copolymers thereof with at least onecopolymerizing substance selected from the class consisting ofalpha-beta unsaturated carboxylic acids, vinyl acetate and vinylalcohol, the said copolymerizing substance constituting 1 to 60 molepercent of the copolymer, the step of applying the said layer to thepolyethylene terephthalate film after the polyethylene terephthalatefilm has been fully biaxially orientated and heat-set.

References Cited UNITED STATES PATENTS 1,241,738 10/1917 Klatte et al260--89.1 2,591,592 4/1952 Harriman 96-87 2,792,303 5/1957 Sanders etal. 96-49 3,023,101 2/1962 Ossenbrunner et al. 9687 3,025,163 3/ 1962Ossenbrunner et al. 9687 2,627,088 2/ 1958 Alles et al. 96-75X 2,943,9377/1960 Nadeau et al. 96--87 2,984,569 5/1961 Huys et al 96-87 3,447,9476/1969 Abbott et al. 117138.8 3,201,249 8/1965 Pierce et al. 9684 (Otherreferences on following page) FOREIGN PATENTS Great Britain 26089.1Great Britain 96-87 Great Britain 9675 Great Britain 9691 Great Britain117138.8 Great Britain 9687 1 2 1,166,616 3/1964 Germany 9687 1,361,7824/1964 France 9-6-87 RONALD H. SMITH, Primary Examiner U.S. C1. X.R.

